Republican primary:
We'll start with the obvious: Carly Fiorina, Lindsey Graham, Bobby Jindal, John Kasich, George Pataki and Jim Gilmore will all fail to get traction and will drop out around the time of the first primaries, if not sooner.
Ben Carson will implode in a comical fashion before the voting starts. "Glyconutrients" will become a metaphor for empty promises.
Rand Paul will have poor fundraising numbers and no money for TV ads. High-level staff members will jump ship, and after Super Tuesday, it will be clearly hopeless. BUT he'll stay in until the very end, just like his dad did in 2008 and 2012. He'll get about 5% of the vote. Once he's no longer viable, many of his potential supporters will ditch him to cross over to the Dem primary to vote for Bernie.
Both Chris Christie and Ted Cruz will be overshadowed by Trump and will drop out after Super Tuesday, after poor showings. Before dropping out, Christie will get into a catfight with Trump and lose badly.
Rick Santorum will likewise be overshadowed by Huckabee and will drop out after the SC primary, or Super Tuesday at the latest. But not before saying at least one thing as stupid as "blah people".
Rick Perry will probably self-destruct spectacularly like he did in 2012. But maybe not. He was clearly on painkillers during that surreal NH speech. Maybe he'll manage his meds better this time around, and make it all the way to a Super Tuesday drop-out.
It will settle down into a Trump, Bush, Walker, Rubio and Huckabee race. In the first few primaries, these five will always finish in the top half. After that, most of the time they will finish in the top five. Each will have LOADS of money to run on, and no particular reason to drop out. It will be "the battle of the billionaires". There will be a LOT of negative ads.
The Christian right will coalesce behind Huckabee, giving him a solid 10-20% of the vote in each pimary.
Walker's multiple scandals will get major press. But just like Perry's indictment, the GOP base will shrug it off as a "partisan witch hunt".
Rubio will probably pull off a narrow win in Florida, but otherwise will finish mostly in the middle of the pack.
Bush will NEVER finish first in any state, except possibly Florida, especially if he cheats somehow. But he will avoid truly disastrous losses, never falling much below 10% of the vote.
Trump will have WAY too much fun. His debate prep will consist of skimming the far right blogosphere for attack material. His debate coach will be Don Rickles.
None of the five will win a majority of the votes, and when the voting ends, the totals will look something like this: Trump is the winner at 25% of the vote. Huckabee comes in last with about 15%. The other three are in the middle.
No one will have a majority of delegates, and it'll be a brokered convention. After many secret back-room deals, the ultimate insider will win: Jeb Bush. The base will be furious!
I don't know who Bush's VP will be. Maybe Kasich or Fiorina. Quite likely Rubio or Walker or even Huckabee, as part of the secret deals. Definitely not Trump.
Trump will financially benefit from all the secret deal-making, but we may or may not find out about it.
Democratic primary:
Biden probably won't get in. If he does get in, he won't get far.
Bernie will keep rising in the polls and Hillary will keep dropping. They'll reach rough parity, especially after the debates. The others will never get much traction.
Bernie will win Iowa and/or NH and it'll be 2008 all over again. Chaffee, O'Malley and Webb will drop out after Iowa, NH or maybe SC for Webb.
TPTB will do everything they can to stop Bernie. They'll try to rig the debate schedule and format in their favor. Same with delegate allocation rules, superdelegates rules, etc. Formerly respected Dems will launch nasty attacks that will backfire. Much like Geraldine Ferraro in 2008 with "If Obama was a white man, he would not be in this position". But this time it will be many if not most establishment Dems. The only Dems endorsing Bernie will be those who don't have significant campaign contributions from the big banks.
Bernie will not run any negative ads, wisely realizing that's the key to tapping into the 40% who don't vote. Many people will register to vote for the first time (or register as a democrat for the first time) specifically to vote for him in the primaries.
Hillary and her superpac will run a TON of negative ads, like her 2008 "3am phone call" ad. They won't have much effect, and may even backfire.
Bernie will win both the most votes and the most delegates in the primaries. But it will be close enough that the superdelegates will matter. If it looks like they will block Bernie, there will be a MAJOR firestorm from the left. Protests in the street as big as the anti-war ones of 2002-2003.
Elizabeth Warren will be Bernie's VP. Bernie will NOT pick a moderate Southerner to "balance the ticket" because that would undercut his strongest selling point, consistency. The Warren pick will probably be announced during the primaries, once he's won enough of them to be clearly viable. Warren will help Bernie win the nomination by appealing to the female-in-the-white-house element, and countering the he's-so-old-what-if-he-dies-in-office argument.
General election:
Trump probably won't go third party. Two reasons: so he can retire from politics as a winner, not a loser. Also so he can call in major favors from the mega-billionaires in exchange for not running. If he does run, he'll get 10-15% of the vote.
The Democratic party will be Bernie's biggest problem. He'll get very lukewarm support from them, and some outright sabotage may happen.
Bush will be stiff and phony. There will be much waffling, and many "clarifications".
Around September, we'll hear a lot about "Sanders Republicans". Also the huge voter registration numbers.
Bernie will be up at least 10 points in the polls, but he'll campaign as if he were 10 points down. He'll campaign in many more places than the usual swing states. He'll endorse and actively campaign for certain Democrats in US House/Senate races. Much like Obama cut a TV ad for Merkeley in 2008 after his Republican opponent tried to ride Obama's coattails (!)
Bernie will CRUSH Bush. With Trump in, Bush's ceiling will be the same 30% who approved of Dubya's presidency on January 2009. Even without Trump, he would get at most Romney's 47%. BUT with all the new Bernie voters, the pie will grow, and Romney's slice will be shrunk to about 40%.
Bernie will have major coattails. There will be a huge turnout on the Dem side. Unless Trump runs, many Republicans will stay home. The Senate will flip, and the House may too.
Fri Aug 07, 2015 at 12:30 PM PT: Updated with a few points:
Bernie will win the Dem primary popular vote by a wider margin that the delegate count, because of dirty tricks, err I mean, "procedural maneuvering" by TPTB.
Bernie's veep will be Warren or someone else about as progressive. It definitely won't be a moderate, but to clarify, it could be a Southerner. (I was referring to the CW on VP picks that makes "moderate Southerner" practically one word.)
To expand on "no particular reason to drop out": In a 5-way race, the bottom 3 will think, "I'm not exactly winning, but no-one else is either, and I'm not losing TOO badly. I've got lots of superPAC money. Why quit? Even if I'm not the nominee, I can increase my national stature, set myself up for 2020 or 2024, maybe even become VP." Huckabee in particular has a history of hanging in right up until his nomination becomes mathematically impossible.
So except for the "Southerner" part, I stand behind my predictions 100%. Over the course of 2016, I'll periodically write diaries on how well my predictions have held up so far. I expect to be about 70% right. See you next year!